Method and configuration for heating buildings with an infrared heater

ABSTRACT

A building is heated using an infrared heater with a radiant tube. A heated gas is fed to the radiant tube at a first end and the tube is further fluidically connected at its second end to a heat exchanger. A portion of the thermal energy contained in the heated gas is conveyed to a buffer storage tank, from which the energy can be removed in particular to heat up industrial water or to heat a second part of a building thermally isolated from the first building, or a second building. There is also provided a solar collector. The feed and/or return of the heat exchanger and/or the feed and/or return of the buffer storage tank can be fluidically connected to the feed and/or return of a thermal solar collector via pipes and switchable valves.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority, under 35 U.S.C. §119, of German patent applications DE 10 2013 004 061.2, filed Mar. 11, 2013, and DE 10 2013 017 677.8, filed Oct. 25, 2013; the prior applications are herewith incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The invention relates to a method and a configuration for heating buildings using an infrared heater. The heating system includes a radiant tube arranged in a first housing and having a first at which gas, heated by a burner, is conveyed, and having a second end fluidically connected to a heat exchanger, which conveys part of the thermal energy contained in the heated gas to a buffer storage tank. The energy can be removed from the buffer to heat up service water or to heat a second part of a building thermally isolated from the first building, or a second building.

Such infrared heaters have been sold by the applicant for a long time. They comprise a housing, which is usually suspended horizontally and open at the bottom, in which a radiant tube is accommodated onto which heated air is directed by a burner, in particular a gas burner, and a fan. Because the temperature generated thereby of the (usually black) outside of the radiant tube is in the region of 300° C. to 750° C., the radiant tube emits infrared radiation in the manner of a black body, which results in direct heating of the environment below the radiant tube. Compared with conventional building heaters, where heating bodies such as, for example, radiators are used, it is hereby advantageous that in a building only the surfaces of people, animals, and objects are heated by the infrared radiation and not the volumes of air inside the building, so that the infrared heaters described operate in a comparatively economical fashion and accordingly are preferably used to heat halls.

The prior art infrared heaters of the above-mentioned type are subject to the disadvantage that the residual heat in the heated gas is used inadequately after it has left the radiant tube, which adversely affects the overall efficiency of the infrared heaters.

Our commonly assigned, published patent application US 2010/0260490 A1 and its counterpart German published patent application DE 10 2007 047 661 A1, describes using a heat exchanger to reclaim part of the residual heat contained in the exhaust gas from infrared heaters in a first building and to store the reclaimed heat temporarily in a buffer storage tank from which the reclaimed residual heat can then be used to heat up service water or industrial water, or conventional heating bodies in a second building, or a thermally isolated part of a building. The latter may, for example, be an office area in the first building that is isolated from the hall area.

Although the overall efficiency can already be increased considerably with the configuration described in US 2010/0260490 A1 and DE 10 2007 047 661, there is a desire to reduce still further the costs which exist when heating buildings using infrared heaters, or to feed in renewable energy, in this case solar energy, in an economically sensible fashion.

SUMMARY OF THE INVENTION

It is accordingly an object of the invention to provide a method and device for heating buildings with an infrared heater which overcome the above-mentioned disadvantages of the heretofore-known devices and methods of this general type and which allow the cost of heating buildings, in particular halls with integrated subareas that are thermally isolated from the remaining area of the hall, can be reduced.

With the foregoing and other objects in view there is provided, in accordance with the invention, a method of heating buildings, the method comprising:

providing an infrared heater with a radiant tube disposed in a first building;

feeding a gas, heated by a burner, into the radiant tube and from the radiant tube to a heat exchanger that is fluidically connected to the radiant tube;

extracting thermal energy from the heated gas in the heat exchanger and conveying part of the thermal energy extracted from the heated gas to a buffer storage tank, wherein the heat exchanger and the buffer storage tank are connected by way of a feed line and a return line; and

selectively connecting, by way of switchable valves, at least one of a feed of the heat exchanger, a return of the heat exchanger, the feed line of the buffer storage tank, or the return line of the buffer storage tank, to one or both of a feed or return of a thermal solar collector; and

making available energy from the buffer storage tank for heating up service water or for heating a second part of a building that is thermally insulated from the first building, or for heating a second building.

In other words, according to the invention, a method and an associated configuration for heating buildings using an infrared heater are described. The heater includes a radiant tube arranged in a first building and to which at a first end a gas, heated by a burner, is conveyed, and which is fluidically connected at its second end to a heat exchanger which conveys part of the thermal energy contained in the heated gas to a buffer storage tank, from which said energy can be removed in particular to heat up industrial water or to heat a second part of a building thermally isolated from the first building, or a second building, is characterized in that the feed and/or return of the buffer storage tank can be fluidically connected to the feed and/or return of a thermal solar collector via pipes and switchable valves.

Expressed differently, the invention comprises a particular combination of a dark radiator heating system, as disclosed in the abovementioned US 2010/0260490 A1 and DE 10 2007 047 661, with one or more likewise known thermal solar collectors, as a result of which considerable advantages follow, in comparison with the individual systems, said advantages being described in detail below.

As was surprisingly discovered by the Applicant, numerous advantages arise from the coupling according to the invention of a thermal solar collector to a dark radiator heating system mentioned at the beginning for heating halls, which do not occur when, for example, such a thermal solar collector is coupled to an oil heater or a classical gas heater. These advantages consist in the fact that the heat exchangers that are installed in these systems are preferably suspended from the hall ceiling. As a result, there are short pipe runs, between the thermal solar collector mounted on the hall roof and the heat exchanger, which reduce connective heat loss and hence further reduce the undesired heating of the air in the hall heated by the dark radiator. Because of the longer pipe runs, this advantage does not occur in conventional gas or oil heaters which are usually fitted in the basement or in another building. A further advantage arises from the fact that the radiation heating systems described at the beginning already comprise a heat exchanger which can be easily modified to receive the additional heat from the solar collector.

Other features which are considered as characteristic for the invention are set forth in the appended claims.

Although the invention is illustrated and described herein as embodied in a method and configuration for heating buildings using an infrared heater, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.

The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 shows a radiation heater configuration of the prior art with a heat exchanger and a buffer storage tank, but no solar collector;

FIG. 2 shows a schematic view of the pipe routing of the radiation heating configuration according to the invention during mixed heating mode;

FIG. 3 shows a schematic view of the pipe routing of the radiation heating configuration according to the invention during thawing mode of a solar collector covered with frost or snow; and

FIG. 4 shows a schematic view of the components and pipe routing for a preferred embodiment of the radiation heating configuration according to the invention by means of which all the operating modes of the method according to the invention can be implemented.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the figures of the drawing in detail and first, particularly, to FIG. 1 thereof, there is illustrated a normal operating condition of a radiation heater, which is in particular used for industrial halls. The figure shows the interconnection, represented as a block diagram, of a dark radiator heater 1 with a heat exchanger 2 and a buffer storage tank 4, and the associated pipes and consumer units. The configuration shown in FIG. 1 represents the basic configuration which is used to heat halls very efficiently. This happens by the use of a dark radiator 1 by way of which the air in a building is heated as little as possible but nevertheless creates a comfortable temperature for the persons who work in the building, for example a large hall. As described in the above-described US 2010/0260490 A1 and DE 10 2007 047 661—which are herewith incorporated by reference—the power which is not delivered as radiant heat is partially reclaimed via a heat exchanger 2, reference being made to the document mentioned for detailed information. The heat exchanger 2 is preferably likewise mounted beneath the hall ceiling. The side of the heat exchanger receiving the heated gas is considered the primary side and the conveying-medium (i.e., water) side that is connected to the storage tank 4 is considered the secondary side.

The consumer units 7, which are indicated only schematically in FIG. 1, are connected to the buffer storage tank 4 via a pipe 8. The consumers 7 can, in particular, be heating bodies in a second building or a thermally insulated subarea of the building in which the infrared radiator 1 is also arranged. Likewise, however, the consumer units can also be the temporary storage tanks of a classical heater that is present.

The buffer storage tank 4 used in FIG. 1, and also the other figures, differs from a classical heat storage tank for oil, gas, or other conventional heating systems in that it is preferably designed with a greater thermal capacity. The design of the buffer storage tank 4 with a greater thermal capacity results in a higher thermal inertia—in control engineering terms of an integral control loop—for radiation heaters than for classical heaters which feed in the heat only via underfloor heating systems or heating bodies. As explained in more detail below, the increased heat storage capacity of the buffer storage tank 4 compared with conventional classical heaters in conjunction with the solution according to the invention is advantageous.

This results because the normal type of operation of the infrared heaters is cyclical operation. During cyclical operation, the operator of the hall presets a desired target temperature in the hall and the infrared radiator 1 switches on and heats the objects and people situated in the hall and a reference point which represents the measuring location. The residual heat content of the exhaust gas 5, 6 which is not used as radiant heat is delivered to the buffer storage tank 4 via the heat exchanger 2. This buffer storage tank 4 can be designed as a mixed storage tank but is particularly advantageously a known stratified storage tank with one or more hot water inlets or outlets in the upper region and one or more cold water inlets and outlets in the lower region. In the case of the stratified storage tank, the heat is discharged in the upper part of the storage tank and the colder portion of the fluid, which is preferably water, is conveyed out of a connector in the lower part of the storage tank 4 by a pump 13, via the pipe 9, via the return RL, into the heat exchanger 2. The cold water removed from the buffer storage tank 4 is heated in the heat exchanger 2 by the hot exhaust gases 5, 6 and is recycled into the upper part of the buffer storage tank 4 via the pipe 10.

In the latter case, a so-called return flow boost of the temperature of the heater return is achieved by the residual heat extracted from the exhaust gas 5, 6 of the dark radiator 1.

According to the embodiment shown in FIG. 2 of a radiation heating configuration according to the invention for carrying out the method according to the invention, which will also be referred to as a mixed heating configuration, a known thermal solar collector 3 is additionally integrated into the supply pipe 9 to the return RL of the heat exchanger 2 and into the pipe 10 which connects the feed VL of the heat exchanger 2 to the inlet on the top of the buffer storage tank 4. This consequently offers the possibility that solar power can be taken from the solar thermal collector 3, in particular during the transition seasons but also to a lesser extent during wintertime, even when this is sometimes no longer possible with conventional solar collectors alone, or is exceedingly inefficient.

In order to achieve this, the feed VL of the solar collector 3 is fluidically connected via a pipe 15 a and a branch piece 20, for example a T-piece or a Y-piece, to the supply pipe 10 which leads from the feed VL of the heat exchanger 2 to an upper inlet of the buffer storage tank 4. Furthermore, the cold water outlet of the buffer storage tank 4 is connected to the return RL of the solar collector 3 via a further branch piece 22, for example a T-piece or Y-piece in the pipe 9 which leads from the lower part of the buffer storage tank 4 to the return RL of the heat exchanger 2, via a supply pipe 15 b. A solar pump 12, and optionally a check valve 26, the flow rate of which is changed depending on the intensity of the solar radiation which is recorded by a known intensity sensor 11, is situated in the supply pipe 15 b.

In order to increase the temperature when there is little sunlight and/or low ambient temperatures, the water which is conveyed through the solar collector 3 by the solar pump 12, is heated in the solar collector 3, and emerges from the feed VL is mixed in the first branch piece 20 with the water which was heated in the heat exchanger 2 when the infrared heater 1 was operating and emerges from the feed VL. The temperature of the water heated in the solar collector 3, which for example is only 30° C. and is too low to be used directly in the thermal consumer units 7 or as service water, is raised to a usable temperature of, for example, 60° C. before the water is fed into the buffer storage tank 4.

The solar collector 3 which is used hereby is preferably mounted on the outside of the roof of the first or second building. This can be either a flat roof or a pitched roof. In particular in the northern parts of North America which correspond in terms of latitude to central European, Eastern European, and Northern European countries, the sunlight strikes the collector 3 with irregular intensity. The heat requirement depends on the purpose for which the building is used, in other words differently at the weekend and during the week and differently during the day and night. The dark radiator heater 1 is here switched on and off cyclically according to the heating needs of the hall and supplies the heat to the heat exchanger 2 via the exhaust gas 5. In the normal control system of the dark radiator heater, this heat is transferred to the buffer storage tank 4 via the pipe 10 and the cooler exhaust gas 6 emerges from the heat exchanger 2. The solar energy is fed into this system in a different cycle determined by the sun.

The normal installation of a solar thermal system without a hall heater includes the necessary installation of the control system, the pipe run of the solar energy system from the roof to the basement/boiler room of the industrial or private premises, and the investment costs of the buffer storage tank. As a result, the pipes and the buffer storage tank or tanks 4, and large parts of the electronic control equipment for an installed heating system according to FIGS. 2 to 4, are already present so that advantageously only a relatively low amount of additional investment is entailed when retrofitting the solution according to the invention.

When there is sufficient solar radiation, the radiated energy is supplied in the form of heat via the pipe 15 a and the pipe 10 ultimately to the buffer storage tank 4. The solar collector 3 receives, from the coldest point of the storage tank 4 via the pump 13, the pipe 9, a T-piece and then the pump 12, cold water from the lower region of the buffer storage tank 4 and conveys it into the solar collector 3. As explained, all the already present installations of the basic configuration shown in FIG. 1 can thus advantageously be reused when retrofitting the solar collector 3. For current solar power systems, the capital cost of the collector 3 itself is usually much less than half the total investment of the whole system, which again makes it advantageous to connect the solar collector to the dark radiator heater.

As can be seen from the view in FIG. 3, during winter conventional solar thermal collectors have the problem that, when snow falls and there is sunshine afterwards, something which is common in higher latitudes, such as North America and central European and neighboring countries, no solar thermal heat is fed in because snow and ice prevent irradiation by the sun. In this case, however, according to another concept which is the subject of the invention, the cold water from the lower part of the buffer storage tank 4 can advantageously be used to melt and clear the snow and ice from the top of the solar collector 3.

To do this, cold water is fed via the solar pump 12 and the pump 13 into the solar collector 3. The water emerging from the feed VL of the solar collector 3 is not heated in this case but instead is cooled by the ice. According to the invention, the cooled water is fed into the return RL, labeled RL, of the heat exchanger 2 via the pipe 16. In order to prevent hereby cooled water from flowing back from the pipe 16 into the return RL of the solar collector 3, a check valve 25 is arranged between the branch piece 23 and the branch piece 22, as shown in FIG. 3. This pipe configuration allows a minimum number of pipes to be required. The cooled water is thus preferably fed from the feed VL of the solar collector 3 only when the dark radiator 1, i.e. the infrared radiation heater, is not switched on. In this case, the cold water is conveyed only through the heat exchanger 2 and passes via the pipe 10 and a first three-way valve 14 and the pipes 17 and 8 to the cold water inlet in the lower part of the buffer storage tank 4. This means that already relatively cold water from the lower part of the buffer storage tank, but which has a temperature much greater than 0° C., for example 30° C., is cooled by deicing the solar collector 3 from, for example, 30° C. to 10° C. and is then fed at the coldest point into the lower part of the buffer storage tank 4, which in this case takes the form of a stratified storage tank.

The advantage of the embodiment shown in FIG. 3 of the configuration according to the invention is that no heat energy at all is wasted and there is no mixing of cold and hot water, which improves efficiency. When the dark radiator 1 is switched on, the very cold water is fed from the feed VL of the solar collector 3 via the pipe 16 and the branch piece 23 into the heat exchanger 2. In this case, the hot exhaust gas 5 from the infrared radiator 1 can be cooled down particularly quickly, which advantageously enables large-scale use of the condensation heat of the exhaust gas of the dark radiator. This in turn results in a significant increase in the efficiency of the whole system. In this case, the water leaves the heat exchanger 2 as hot or warm water and is preferably fed into the upper region of the storage tank 4 via the first three-way valve 14.

As a result of the configuration according to the invention shown in FIG. 3 and FIG. 4, and the method according to the invention described in the claims, the likewise known problem can also be overcome that, in the case of the known solar thermal collectors 3, the temperature falls below the dew point in the early hours of the morning when the outside temperatures are above freezing point and the solar collector is not covered with snow and ice. Because the temperature falls below the dew point, the dew that occurs on the surfaces of the collector reflects back the sun's rays, which greatly reduces the solar thermal power. The dew can be evaporated via the heating of the solar collector by the water from the buffer storage tank 4, or also directly by the waste heat that occurs when the dark radiator 1 starts up for the first time in the morning, without the additional use of primary energy, as a result of which the solar collector 3 reaches its full capacity within a very short time.

The sensor 11 hereby preferably detects, likewise via the recorded intensity of the solar radiation and/or the temperature of the solar collector 3, when either the ice or the snow has thawed away, or when the condensation/dew has evaporated, at which point the system is immediately switched to the mixed operating mode described in conjunction with FIG. 2. This provides the advantage that the thawing or evaporation takes only a few minutes and the full capacity of the solar collector 3 is then available to heat the water in the buffer storage tank 4. A further advantage of this embodiment of the invention consists in the fact that the thermal energy used for the thawing or dew removal normally has no usefulness because the temperature is too low.

According to a further concept which is a subject of the invention, the application of the method according to the invention or the associated configuration makes it possible to raise the temperature of the solar-heated water to a usable level without using a heat pump or the like. The reason for this is that in a transitional period, in particular in spring or fall, at outside temperatures at which heating is normally required, the solar thermal collectors are no longer capable of providing adequate amounts of hot water at a sufficiently high temperature which is required by current conventional heating systems for economic operation. The simultaneous drop in the outside temperature and the associated increased losses from the reduced radiation of the sun which is low in the sky in the transition seasons result in, for example, a water temperature of only 40° C. being achieved. By virtue of the combination according to the invention of an IR radiation heater and a thermal solar collector 3, the temperature of the water can be raised, with the embodiment shown in FIG. 3, from, for example, 40° C. to 60° C., as a result of which this can be used directly in a conventional convection heater in the thermally isolated building part, or can be fed into the upper part of the buffer storage tank 4.

In the present application of the configuration shown in FIG. 3, in which there is preferably a minimum flow control, this is achieved by returned water, for example from a conventional convection heating body 7, entering via the pipe 8 at approximately 30° C. into the lower part of the buffer storage tank 4, from where it is conveyed via the pumps 12 and 13 into the solar collector 3 in which it is heated, for example, to just 40° C. When the dark radiator 1 is running, the heated water is then pumped via the pipe 16 and the branch piece 23 into the return RL of the heat exchanger 2 in order to be reheated there to 60° C. or more. The water is next profitably fed via the first three-way valve 14 into the upper part of the buffer storage tank 4. In this case, therefore approximately ⅓ of the energy can be contributed by the thermal solar collector 3, which would not have been possible without the additional use according to the invention of the dark radiator 1 because, without the latter, the flow temperature of the solar collector 3 is too low to be able to make efficient direct thermal use of the heat energy radiated by the sun. When the dark radiator is not operating, the first three-way valve 14 is switched through so that the water emerging from the feed VL of the heat exchanger 2, which in this case was not additionally heated up in the heat exchanger 2, is fed via the pipe 17 into the lower part of the buffer storage tank 4.

A further advantageous embodiment of the configuration according to the invention with the complete pipework, shown by way of example, and the necessary pumps and valves is shown in FIG. 4, in this case a first and a second three-way valve 14 and 24 being used in order to be able to operate the configuration according to the different embodiments of the method according to the invention.

As can be seen hereby in detail in the view in FIG. 4, as a supplement to the configuration in FIG. 3, the feed VL of the solar collector 3 can be connected via a second three-way valve 24 or via the pipe 16 and the T-piece 23 to the return RL of the heat exchanger 2 or the supply pipe 10 which is fluidically connected to the feed VL of the heat exchanger 2 via a branch piece 23. As already described above in conjunction with the configuration in FIG. 3, the supply pipe 10 can be connected via the first further three-way valve 14 either to the hot water inlet in the upper part of the buffer storage tank 4 or via the pipe 17 to the cold water inlet in the lower part of the buffer storage tank 4.

In order to operate the configuration in FIG. 4 in the mixed operating mode shown in FIG. 2, the pump 13 and the solar pump 12 are switched on. They convey cool water from the lower part of the buffer storage tank 4, via the pipe 9, the branch piece 22, and the pipe 15 b, to the return RL of the solar collector 3. The heated water which emerges from the solar collector 3 and has been heated sufficiently so that it can be used directly in the heating devices 7 is then fed via the second three-way valve 24 into the pipe 15 a. It passes through the latter via the branch piece 20 and the pipe 10 to the first three-way valve 14 which is switched such that the water is fed into the upper part of the buffer storage tank 4. From there, the hot water, at for example 60° C., is supplied, when required, directly to the heating devices 7 in which it discharges part of the heat energy contained, before it is fed via the supply pipe 8 back into the lower part of the buffer storage tank 4.

If the temperature of the water emerging from the feed VL of the solar collector 3 is too low for it to be able to be used directly in the heating devices 7, for example in the transition seasons, when the dark radiator 1 is not operating, the first three-way valve 14 is switched and the cool water is fed into the lower part of the buffer storage tank 4 via the pipe 17. To do this, a temperature sensor, not shown in detail in the drawings, can be provided in the pipe 10 or at the first three-way valve 14 itself, and depending on which the first three-way valve 14 is switched in order to feed the water into the upper or lower part of the buffer storage tank 4.

If the dark radiator 1 is switched on in this operating status and receives a signal from the solar sensor 11 that the sun is shining only with low intensity, the second three-way valve 24 is switched and the cool water emerging from the feed VL of the solar collector 3 is fed via the pipe 16 and the branch piece 23 into the return RL of the heat exchanger 2 in order to raise its temperature to a level where it can be fed directly into the upper part of the buffer storage tank 4. The additionally heated water emerging from the feed VL of the heat exchanger 2, the temperature of which was raised in the heat exchanger 2 preferably to above 60° C., is fed via the pipe 10 and the correspondingly switched first three-way valve 14 directly into the upper part of the buffer storage tank 4, from which it is taken by the heating devices as required and fed back, cooled, via the pipe 8 into the lower part of the buffer storage tank.

If there is no solar intensity at all recorded by the sensor 11 in the early-morning hours when the heating system is first switched on, even though the sun has already risen, the second three-way valve 24 is switched to thaw snow or remove dew from the collector in such a way that the feed VL of the solar collector 3 is connected to the return RL of the heat exchanger 2 via the pipe 16 and the branch piece 23. A check valve 25 is preferably situated between the branch pieces 22 and 23 of the collector circuit in order to hereby prevent the water cooled in the collector 3 from flowing via the branch piece 23 into the supply pipe 15 b. When the temperature of the water emerging from the feed VL of the heat exchanger 2 is high enough for it to be able to be used directly by the consumer units 7, the first three-way valve 14 is switched such that the water which is circulated via the pump 13 and the pipe 9 and the solar pump 12 by the solar collector 3 and the heat exchanger 2 is fed into the upper part of the buffer storage tank 4 via the pipes 10.

It is alternatively possible for the collector 3 to be thawed particularly efficiently before the dark radiator 1 is started up for the first time as long as the dark radiator 1 is switched off. This ensures that only cold water is pumped from the lower part of the buffer storage tank 4 through the solar collector 3, the water heating the solar collector 3 in order to remove snow and ice, as well as dew, from the surface of the collector 3. The cold water that is taken from the lower part of the buffer storage tank 4 through the pipe 9 when the dark radiator 1 is switched off is fed into the return RL of the collector 3 by the solar pump 12 via the branch piece 22 and the supply pipe 15 b and preferably conveyed back into the lower part of the buffer storage tank 4 via the second three-way valve 24 and the pipe 15 a, the branch piece 20, the pipe 10, the first three-way valve 14 and the pipe 17. As a result, the efficiency of the overall system can advantageously be increased even further because only cold water is used to thaw the collector 3, said water then being fed back again into the lower part of the buffer storage tank, from which it can be taken to be heated by the heat exchanger 2 when the dark radiator 1 is running.

As soon as the solar sensor 11, which is preferably integrated into the collector face facing the sun, measures a sufficiently high solar intensity, the second three-way valve 24 is switched and the water which emerges from the feed VL of the solar collector 3 and is heated by the solar radiation is fed via the branch piece 23 into the heat exchanger 2, in which the temperature of the water when the dark radiator 1 is switched on is raised preferably above a temperature of 60° C. so that it can be fed, via the correspondingly switched first three-way valve 14, into the upper part of the buffer storage tank 4 for direct use by the consumer units 7. If the temperature of the water heated in the heat exchanger 2 is lower, which was recorded, for example, by the abovementioned sensor in the supply pipe 10 or in the first three-way valve, the water is fed into the lower part of the heat exchanger via the pipe 17.

Lastly, for the situation where in winter the solar collector 3 contributes no additional heat when there is a lack of solar radiation and very low ambient temperatures, it can be provided that the circulation of water through the solar collector 3 can be interrupted by a stop valve 26 connected upstream from the solar pump 12.

The pumps 12 and 13 and the first and second three-way valves 14, 24 are preferably controlled by a known electronic control device, not shown in detail in the drawings, which is correspondingly connected to the abovementioned sensors.

The other features of the invention are described in the dependent claims, which are hereby explicitly included in the content of the description of the present application.

The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention:

-   -   1 Infrared heater     -   2 Heat exchanger     -   3 Solar collector     -   4 Buffer storage tank     -   5 Exhaust gas entering the heat exchanger     -   6 Exhaust gas emerging from the heat exchanger     -   7 Consumer unit     -   8 Pipe from the consumer unit to the cold water inlet of the         buffer storage tank     -   9 Pipe from the cold water outlet of the buffer storage tank to         the branch piece/return of the heat exchanger     -   10 Pipe from the heat exchanger to the first three-way valve     -   11 Sensor for solar intensity     -   12 Solar pump     -   13 Pump     -   14 First three-way valve     -   15 a Pipe from the feed VL of the solar collector to the branch         piece 20     -   15 b Pipe from the branch piece 22 in the pipe 9 to the return         RL of the solar collector     -   16 Pipe between the second three-way valve and the branch piece         23 upstream from the return RL of the heat exchanger     -   17 Pipe from the first three-way valve to the cold water inlet         in the lower part of the buffer storage tank     -   20 Branch piece in the supply pipe 10     -   22 Branch piece in the supply pipe 9     -   23 Further branch piece in the supply pipe 9 between the return         RL of the heat exchanger and the check valve 25     -   25 Check valve     -   26 Stop valve 

1. A method of heating buildings, the method comprising: providing an infrared heater with a radiant tube disposed in a first building; feeding a gas, heated by a burner, into the radiant tube and from the radiant tube to a heat exchanger fluidically connected to the radiant tube; extracting thermal energy from the heated gas in the heat exchanger and conveying part of the thermal energy extracted from the heated gas to a buffer storage tank, wherein the heat exchanger and the buffer storage tank are connected by way of a feed line and a return line; and selectively connecting, by way of switchable valves, at least one of a feed of the heat exchanger, a return of the heat exchanger, the feed line of the buffer storage tank, or the return line of the buffer storage tank, to one or both of a feed or return of a thermal solar collector; and making available energy from the buffer storage tank for heating up service water or for heating a second part of a building that is thermally insulated from the first building, or for heating a second building.
 2. The method according to claim 1, which comprises increasing a temperature of water warmed by and emerging from the solar collector when there is little sunlight or low ambient temperatures, by mixing the water emerging from the solar collector with water that was heated in the heat exchanger when the infrared heater was operating, before feeding the water into the buffer storage tank.
 3. The method according to claim 2, which comprises, in order to increase a temperature of the water heated by the solar collector, fluidically connecting the feed of the solar collector via a branch piece to the feed of the heat exchanger, and providing a solar pump and a sensor recording an intensity of the solar radiation, enabling a flow of water to the return of the solar collector to be altered.
 4. The method according to claim 3, which comprises connecting the feed of the solar collector via a T-piece or a Y-piece to the feed of the heat exchanger.
 5. The method according to claim 3, which comprises connecting a cold water outlet of the buffer storage tank to the return of the heat exchanger and the return of the solar collector via a further branch piece.
 6. The method according to claim 3, wherein the further branch piece is a T-piece or a Y-piece.
 7. The method according to claim 1, which comprises fluidically connecting the return of the solar collector to a cold water outlet of the buffer storage tank to heat the solar collector, if needed, in order to thaw ice on a surface of the solar collector or to remove dew formed inside the collector.
 8. The method according to claim 7, which comprises fluidically connecting the feed of the solar collector to the cold water inlet of the buffer storage tank in order to selectively feed cold water into the cold water inlet of the buffer storage tank when thawing the collector.
 9. The method according to claim 8, which comprises feeding the cold water into the cold water inlet of the buffer via a three-way valve.
 10. The method according to claim 1, which comprises selectively connecting the feed of the solar collector to the feed of the heat exchanger in order to additionally increase a temperature of the water heated in the solar collector before feeding the water into the buffer storage tank.
 11. The method according to claim 10, which comprises selectively connecting the feed of the solar collector to the feed of the heat exchanger via a branch piece.
 12. A configuration for heating buildings, comprising: an infrared heater disposed in a first building and having a radiant tube receiving, at a first end thereof, a gas, heated by a burner, and conveying the gas through a second end thereof and through a fluidic connection to a heat exchanger; a heat exchanger fluidically connected to the second end of said radiant tube for receiving from said radiant tube heated gas, said heat exchanger having a secondary side with a feed and a return; a buffer storage tank fluidically connected to said heat exchanger via a feed and a return and receiving from said heat exchanger part of a thermal energy contained in the heated gas received from said radiant tube; a thermal solar collector having a feed and a return fluidically connected with pipes and switchable valves configured to enable selective fluidic connection of the solar collector to one or more of the feed and/or return of the heat exchanger and/or the feed and/or return of the buffer storage tank; and wherein said buffer storage tank is connected to enable a removal of energy therefrom for heating up industrial water or to heat a second part of a building thermally isolated from the first building, or a second building.
 13. The configuration according to claim 12, configured for carrying out the method according to claim
 1. 14. The configuration according to claim 12, wherein: said buffer storage tank is a stratified storage tank; said feed of said solar collector is selectively connectable by a three-way valve and via a supply pipe to the return of said heat exchanger or via a supply pipe and a branch piece to the feed of said heat exchanger; and said branch piece is selectively connectable, by a supply pipe and a downstream further three-way valve, to a hot water inlet in an upper part of said buffer storage tank or to a cold water inlet in a lower part of said buffer storage tank.
 15. The configuration according to claim 14, wherein the cold water outlet of said buffer storage tank is connectable to the return of said solar collector and to the return of said heat exchanger via a supply pipe and a further branch piece, and wherein the feed of said solar collector is connectable to the return of said heat exchanger via a pipe and a branch piece.
 16. The configuration according to claim 15, wherein said further branch piece is a T-piece or a Y-piece. 